In industrial manufacturing environments, it is often desired to communicate to all of the employees that a process change has or is about to occur in order to synchronize the activities of the individuals who are working on different aspects of the process. Typically, industrial manufacturing facilities are large buildings or industrial complexes. The individuals who work on different aspects of the manufacturing process can therefore be at various locations within the manufacturing facilities.
To accomplish synchronization, chime devices that generate sounds, such as individual or groups of tones, are utilized to communicate information to the individuals at the manufacturing site. In addition, because industrial manufacturing environments often involve a large number of machines that generate a lot of noise during operation, chime devices are utilized to generate sounds that are distinguishable over the noisy environment.
The chimes generated from the chime devices may become inconsistent from one device to another because of unstable electrical components in the circuitry responsible for generating the chime. The instability of the chime circuitry can be attributed to the effects of the temperature at the location of the chime device on the circuit components. The output voltages of some circuit components, such as integrated circuits, transistors, and diodes, vary according to the ambient temperature.
In addition, circuit components, the performance of which depends on the voltage from the temperature-sensitive component, may not perform as expected if the voltage received by the dependent circuit component is not the voltage anticipated to be received by the dependent circuit component.
Accordingly, it is desirable to provide a chime device that has tone-generating circuitry that is not affected by variances in temperature. However, there are instances when an individual may want to purposely alter a tone. For example, an individual may want to extend the length of time that a particular chime plays. Accordingly, it is also desirable to provide tone-generating circuitry that is programmable to produce chime outputs of variable lengths.